common minnesota spiders

Project Fab

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19-03-2025

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Common Minnesota Spiders: A Guide to Eight-Legged Neighbors

Minnesota, with its diverse landscapes ranging from prairies and forests to lakes and wetlands, provides a habitat for a variety of spider species. While many are harmless and even beneficial, encountering an unknown spider can spark concern. This comprehensive guide explores some of the most common spiders found in the state, detailing their appearance, habitat, behavior, and potential for causing harm. Understanding these arachnids can help foster a healthy respect and coexistence.

1. The American House Spider ( Parasteatoda tepidariorum)

This is arguably the most ubiquitous spider in Minnesota homes. The American house spider is a small to medium-sized spider, typically measuring between 6-10mm in body length. Its coloration is variable, ranging from light brown to dark grayish-brown, often with a mottled or speckled appearance. The abdomen is generally rounder than its cephalothorax (head and chest). They construct irregular, messy webs in dark, undisturbed corners, often in basements, garages, attics, or behind furniture. These webs are typically sticky and serve to trap prey, mostly small insects.

American house spiders are not considered medically significant. Their bite is unlikely to cause more than a mild, localized reaction similar to a mosquito bite. While their presence can be unsettling, they play a crucial role in controlling household insect populations.

2. The Common Orb Weaver ( Araneus diadematus)

Recognizable by its large, intricate orb webs, the common orb weaver is a frequent sight in gardens, fields, and wooded areas across Minnesota. These spiders are medium-sized, typically reaching 10-18mm in body length. The female's abdomen is distinctively marked with a characteristic white cross pattern, giving rise to its alternative name, the "cross spider." Males are significantly smaller than females and have less distinct markings. They build their large, spiral webs in vegetation, often between branches or in tall grasses, waiting patiently for unsuspecting insects to become entangled.

While their bite is mildly venomous, it is not considered dangerous to humans. The effects are usually limited to a localized, temporary pain and mild swelling. They are generally shy and unlikely to bite unless directly provoked.

3. The Wolf Spider ( Lycosidae family)

Minnesota is home to numerous wolf spider species, characterized by their large size, hairy bodies, and hunting habits. These spiders are typically dark brown or black, with varying patterns and markings depending on the species. They range in size from 10mm to 30mm in body length. Unlike web-building spiders, wolf spiders are active hunters, roaming the ground in search of prey. They have excellent eyesight and are fast and agile. They often live under rocks, logs, or in leaf litter.

While the bite of a wolf spider can be painful, similar to a bee sting, it is rarely dangerous to healthy adults. However, individuals with allergies to insect venom may experience a more severe reaction.

4. The Jumping Spider ( Salticidae family)

Jumping spiders are easily identified by their robust bodies, large forward-facing eyes, and remarkable jumping ability. They are relatively small, ranging from 3mm to 15mm in body length, and display a variety of colors and patterns. Their excellent vision allows them to accurately judge distances before leaping on their prey. They are active hunters, found in various habitats, including gardens, buildings, and forests.

Jumping spiders are not considered dangerous to humans. Their bite is weak and usually causes only minor discomfort. They are often regarded as fascinating creatures due to their intelligence and hunting behavior.

5. The Yellow Sac Spider ( Cheiracanthium mildei)

Yellow sac spiders are small, pale-yellow to light brown spiders known for their pale legs and their tendency to build irregular, silken retreats or "sacs" where they rest during the day. They are active hunters at night. They are relatively small, reaching only 5-10mm in body length. Their bite is often described as painful, and though rarely serious, it can cause localized pain, swelling, and sometimes a mild necrotic lesion. However, their venom is not considered medically significant, and complications are rare.

6. The Cellar Spider ( Pholcidae family)

Often mistaken for daddy longlegs, cellar spiders are characterized by their long, thin legs and small bodies. Their legs are significantly longer than their body, which is usually pale brown or gray. They are found in dark, damp areas, such as basements, cellars, and caves, building tangled, irregular webs.

Cellar spiders are harmless to humans. Their fangs are too weak to penetrate human skin, and they pose no threat.

7. The Fishing Spider ( Dolomedes tenebrosus)

As their name suggests, these large, semi-aquatic spiders are found near bodies of water. They are brown or dark brown, with distinctive markings and long, spiny legs. They can reach up to 30mm in body length. They are adept swimmers and hunters, often found near lakes, ponds, and streams, preying on aquatic insects and small fish.

While their bite can be painful, fishing spiders are not considered medically significant, and their venom is not harmful to humans.

8. The Black Widow ( Latrodectus species)

While less common than other spiders on this list, black widows do exist in Minnesota. They are easily recognized by the distinctive red hourglass marking on their abdomen. They are much smaller than commonly perceived and their bite can be dangerous, however, antivenom exists and fatalities are very rare. Medical attention is recommended immediately following a suspected bite.

Important Note: While most spiders in Minnesota are harmless or pose only minimal risk, it's crucial to exercise caution. If you are bitten by a spider and experience severe symptoms such as intense pain, swelling, nausea, or difficulty breathing, seek immediate medical attention.

This guide is intended for informational purposes only. Always exercise caution when handling spiders, and if unsure about the identity of a spider, it's best to leave it undisturbed. Learning to identify common spiders can help alleviate anxieties and promote a greater understanding of these often-misunderstood creatures.